Nozzles having an adjustable cross-section

ABSTRACT

A jet propulsion nozzle comprising a plurality of actuated flaps articulated at their upstream ends about substantially tangentially disposed axes distributed circumferentially around the downstream portion of a fixed nozzle duct, said flaps being adapted, under the control of a plurality of actuators, to pivot about their respective axes in order to vary the cross-sectional area of the nozzle, said nozzle comprising furthermore a plurality of intermediate levers separate from the actuators and disposed respectively each between two consecutive actuated flaps, each of said levers being connected through the medium of connecting rods to the two consecutive actuated flaps and being itself articulated about a substantially tangential axis, wherein the flap axes and the intermediate lever axes are carried by a system of longitudinal side plates distributed circumferentially about the nozzle axis and themselves carried by the fixed duct of the nozzle and extending downstream beyond the downstream extremity of said duct, and wherein the geometric figure described, on the one hand by the respective points of articulation of one and the same connecting to a actuated flap and to an intermediate lever and on the other hand by the respective intersections with one of said side plates of the axes of said flap and said lever, is substantially a parallelogram which is capable of deforming during variations in crosssectional area of the nozzle, while nevertheless maintaining one fixed side which is constituted by a straight line section extending within said plate and joining said intersections in which each actuator has a moving part which is fastened to a cross-bar which extends in a tangential direction, relative to the nozzle and connects the two connecting rods associated with the respective flap, and in which the trace of each of said cross-bars onto the plane of the associated deformable parallelogram is separated from the fixed side of said parallelogram, at any moment, by a distance which is less than the height of said parallelogram.

United States Patent [191 Camboulives et al.

[ 51 Sept. 24, 1974 NOZZLES HAVING AN ADJUSTABLE CROSS-SECTION [75] Inventors: Andre Alphonse Mederic Leon Camboulives, Savigny-sur-Orge; Gerard Ernest Andre Jourdain, Evry; Theophile Francois Le Maout, Cesson, all of France [73] Assignee: Societe Nationale DEtude et de Construction de Moteurs dAviation, Paris, France [22] Filed: Oct. 2, 1973 [21] Appl. No.: 402,836

[30] Foreign Application Priority Data Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-John J. Love [5 7] ABSTRACT A jet propulsion nozzle comprising a plurality of actuated flaps articulated at their upstream ends about substantially tangentially disposed axes distributed circumferentially around the downstream portion of a fixed nozzle duct, said flaps being adapted, under the control of a plurality of actuators, to pivot about their respective axes in order to vary the cross-sectional area of the nozzle, said nozzle comprising furthermore a plurality of intermediate levers separate from the ac tuators and disposed respectively each between two consecutive actuated flaps, each of said levers being connected through the medium of connecting rods to the two consecutive actuated flaps and being itself articulated about a substantially tangential axis, wherein the flap axes and the intermediate lever axes are carried by a system of longitudinal side plates distributed circumferentially about the nozzle axis and themselves carried by the fixed duct of the nozzle and extending downstream beyond the downstream extremity of said duct, and wherein the geometric figure described, on the one hand by the re spective points of articulation of one and the same connecting rod to an actu ated fla p and to air intermediate le verarid 'afiiiieafiier hand b y the respective intersections with one of said side plates of the axes of said flap and said lever, is substantially a parallelogram which is capable of deforming during variations in cross-sectional area of the nozzle, while nevertheless maintaining one fixed side which is constituted by a straight line section extending within said plate and joining said intersections in which each actuator has a moving part which is fastened to a cross-bar which extends in a tangential direction, relative to the nozzle and connects the two connecting rods associated with the respective flap, and in which the trace of each of said cross-bars onto the plane of the associated deformable parallelogram is separated from the fixed side of said parallelogram, at any moment, by a distance which is less than the height of said parallelogram.

1 Claim, 7 Drawing Figures PATENTEUSEPZMBM SHEET 10F 5 PAIENIEDSEPZMBH SHEEI '& 0F 5 NW. :mfi

NOZZLES HAVING AN ADJUSTABLE CROSS-SECTION The present invention relates, in a general way, to nozzles having an adjustable cross-sectional area which are intended to be fitted, in particular, to jet propulsion engines such as gas turbine jet propulsion engines.

The invention is more particularly concerned with a jet propulsion nozzle of the type comprising: a fixed structure comprising a fixed nozzle duct; a plurality of actuated flaps which are distributed circumferentially around, and in the prolongation of, the downstream part of the said fixed nozzle duct, and of which each one is hinged, about a first geometrical axis which is substantially tangential in relation to the nozzle, to the said fixed structure, in such a way as to vary the crosssectional area of the said nozzle; a plurality of actuators, each of which corresponds to an actuated flap and comprises a moving part which makes it possible to rotate the said flap about the said first geometrical axis; a plurality of intermediate levers which are disposed in alternation with the said flaps and each of which is hinged, about a second geometrical axis which is substantially tangential in relation to the nozzle, to the said fixed structure; a plurality of connecting rods, each of which is hinged, on the one hand, to an actuated flap, about a third geometrical axis which is substantially tangential in relation to the nozzle end, on the other hand, to an intermediate lever adjacent to the said flap, about a fourth geometrical axis which is substantially tangential in relation to the nozzle, in such a way that there are associated with each actuated flap, two connecting rods by means of which the said flap is connected, respectively, to the two intermediate levers which enframe it; the said first, second, third and fourth geometrical axes, which relate to an actuated flap and to an intermediate lever adjacent to the latter, being disposed in such a way, relative to one another, that the quadrilateral which they determine by their respective traces onto a plane containing the axis of the nozzle, is substantially a parallelogram which is deformed during variations in the cross-sectional area of the nozzle, the said deformable parallelogram having a fixed side constituted by the segment of straight line which connects the traces, onto the said plane, of the said first and second geometrical axes, and a moving side which is substantially parallel to the said fixed side and is constituted by the segment of straight line which connects the traces, on the same plane, of the said third and fourth geometrical axes, the said fixed side and the said moving side being separated from one another by a variable distance which constitutes the height of the deformable parallelogram.

The aim of the present invention is to improve a nozzle of the type described above, with a view to increasing the efficiency with which force is transmitted between each actuator and the actuated flap associated with it. More specifically, the aim of the invention is to make it possible either to increase for a given size of the actuator the driving torque applied to the flap, or else to reduce for a given driving torque the dimensions (particularly the overall dimensions in the radial direction) of the said actuator.

For this purpose, the moving part (for example a rod) of each actuator corresponding to an actuated flap, is fastened, in a nozzle according to the present invention, to a cross-bar which extends in a substantially tangential direction, relative to the nozzle, and connects the two connecting rods associated with the said flap, this rocking link being disposed in such a way that its trace, onto the plane of the above-mentioned deformable parallelogram, is separated from the fixed side of the parallelogram, at any moment, by a distance which is smaller than the height of this parallelogram.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view, in perspective, of a portion of nozzle having an adjustable cross-sectional area according to prior art;

FIG. 2 diagrammatically illustrates this same nozzle, viewed in section through a plane passing through the axis of the said nozzle;

FIG. 3 is a view which is similar to that in FIG. 2 and illustrates the general principle underlying a nozzle which has been improved in accordance with the present invention;

FIG. 4 is a developed plan view, partially cut away, of a portion of nozzle according to one embodiment of the present invention;

FIG. 5 is a section, taken along the line VV, of the portion of nozzle illustrated in FIG. 4;

FIG. 6 is a section, taken along the line VIVI, of the portion of nozzle illustrated in FIG. 4; and

FIG. 7 is a diagrammatic view, in perspective, of the portion of nozzle illustrated in FIGS. 4, 5 and 6.

A diagrammatic illustration has been given, in FIGS. 1 and 2, of a portion of nozzle according to the prior art, the said nozzle forming part of a jet propulsion engine (not illustrated).

This nozzle comprises a fixed structure 1, which itself comprises a fixed nozzle duct (not illustrated), and a plurality of actuated flaps 2 distributed circumferentially around, and in the prolongation of the downstream part of the said fixed duct.

Each actuated flap 2 is hinged about a first geometrical axis A which is substantially tangential in relation to the nozzle, to the fixed structure 1, in such a way as to vary the cross-sectional area of the nozzle. An actuator 3 disposed in the longitudinal direction of the nozzle is provided for each actuated flap 2. As shown in FIG. 2, each actuator 3 comprises a moving part (such as a rod) 4 which makes it possible to rotate the said flap about its axis of articulation A.

The nozzle also comprises a plurality of intermediate levers 5 (also called synchronization levers) which are disposed in alternation with the actuated flaps 2 and of which each one is hinged, about a second geometrical axis B which is substantially tangential in relation to the nozzle, onto the fixed structure 1.

Associated with each actuated flap 2 are two connecting rods 6a, 6b by means of which the said flap is connected, respectively, to the two intermediate levers 5 which enframe it. Each link 6a or 6b, is hinged, on the one hand, to an actuated flap 2, about a third geometrical axis C which is substantially tangential in relation to the nozzle, and, onto the other hand, on an intermediate lever 5 adjacent to the said flap, about a fourth geometrical axis D which is substantially tangential in relation to the nozzle. As shown in FIGS. 1 and 2, the rod 4 of the actuator 3 is hinged on a point on the flap 2 which is situated on the geometrical axis C.

As shown in FIGS. 1 and 2, the four geometrical axes of articulation A, B, C, D relating to an actuated flap 2 and to an intermediate lever 5, which is adjacent to the latter, are so disposed, relative to one another, that the quadrilateral which they determine by their respective traces onto a plane containing the axis of the nozzle (under the circumstances, the plane in FIG. 2), is substantially a parallelogram ABCD which is deformed during variations in the cross-sectional area of the nozzle.

This deformable parallelogram comprises a fixed side AB (see FIG. 2) constituted by the segment of straight line which connects the traces, onto the abovementioned plane, of the axes A and B; it also comprises a moving side CD which is substantially equal and parallel to the side AB and is constituted by the segment of straight line which connects the traces, onto the same plane, of the axes C and D. The fixed side AB and the moving side CD are separated from one another by a variable distance, which constitutes the height h, of the deformable parallelogram.

FIG. 3 illustrates, still in a very diagrammatic manner, an adjustable nozzle which has been improved according to the invention.

The main elements already illustrated in FIGS. 1 and 2 will again be found in this figure, namely: a fixed structure 101, an actuated flap 102, an actuator jack 103 fitted with a moving rod 104, an intermediate (or synchronization) lever 105, connecting rods 106a and 106b, and the four tangential axes A, B, C, D, the traces of which are distributed, as before, along the vertices of a deformable parallelogram ABCD having a fixed side AB.

In contrast, however, to what was provided in the case of FIGS. 1 and 2, the rod 104 of the actuator 103 is no longer hinged directly to the flap 102, but to a crossbar 107 (more clearly visible in FIGS. 4 to 7) which connects the two connecting rods 106a and 10612 associated with the said flap. This cross-bar extends in a direction which is substantially tangential in relation to the nozzle, and its trace onto the plane of the para]- lelogram ABCD has been designated by the reference symbol E in FIG. 3. As can be seen and this observation is essential the point E is selected in such a way that the distance between this point and the fixed side AB of the parallelogram is, at each moment, smaller than the height h, of the said parallelogram.

Consideration will now be given to the advantages of this arrangement over the arrangement as illustrated in FIG. 2.

The following designations will hereinafter be used, with reference to FIGS. 2 and 3:

D, (D,) the maximum outside diameter of the actuator 3 (103);

e, (e,) the mean radial distance between the fixed structure 1 (101) and that generatrix of the said actuator which is closest to the said fixed structure;

H, (H,) the mean radial distance between the fixed structure 1 (101) and that generatrix of the said actuator which is furthest off the said fixed structure;

d, ((1,) the mean radial distance between the fixed structure 1 (101) and the rod 4 (104) of the said actuator;

F, (F,) the force supplied by the actuator 3 (103);

M, (M the moment of the force F, (F relative to the axis of articulation A of the said flap.

4 As shown in FIG. 2, the following are obtained:

H] D1 e and M, F, X h,, where d, h,.

As shown in FIG. 3, the following are obtained:

It will be noted, in the case of this Figure, that, be cause the connecting rods 106a and 10611 are rigid, and the points C and D of these connecting rods belong to the deformable parallelogram ABCD, the displacements of the point E of these rods, when this parallelogram is deformed, are always equal and parallel to those of the points C and D. Since the works of the forces exerted at each of the points C, D and E are equal to one another, the result is that the forces ap plied at C to the flap 102 is always equal and parallel to the force F applied at E by the actuator 103.

The following are therefore obtained:

M2 F2 X hz where In order to establish a basis for consideration, it will be assumed, hereinafter, that e, e e, and that the two actuators 3 and 103 are supplied with driving fluid under the same pressure.

It will be assumed, to begin with, that it is desired to obtain, in both cases, the same driving moment M in relation to the axis of articulation A of the actuated flap 2 or 102 (M, M M).

It is inferred from this that F, X h, F, X 11,.

If it is then assumed that h, h,, the result is that F, F,, and that D, D,.

The arrangement according to the invention therefore has the initial advantage of making it possible, while retaining the same driving moment which is exerted upon the flaps, to reduce the power and diameter of the actuators 103 compared with the actuators 3.

On the other hand, since D, D,, D, e D, e is also obtained, and hence H, I-l,.

The second advantage of this arrangement is that it makes it possible, under the same conditions, to reduce the overall dimension H in the radial direction involved by the actuators 103, compared with the overall dimension H, which results from the presence of the actuators 3. The surprising result is thus arrived at, that the consequence of increasing the height of the deformable parallelogram ABCD is a reduction in the total overall dimension involved by the actuators for controlling the flaps.

It will now be assumed that the same actuators (F, F2), and the same position of this actuator in relation to the fixed structure 1 (101) of the nozzle (d, =d are retained.

It will then be seen, from FIG. 3, that h, hence M M,.

The arrangement according to the invention therefore has the advantage of making it possible, with equal power from the actuator, to increase the driving moment exerted by this actuator upon the flap.

FIGS. 4 to 7 illustrate a practical embodiment of an adjustable nozzle according to the invention. In these figures, the same reference numerals have been used to designate the components already described in connection with FIG. 3.

h,, and

The nozzle therefore comprises a fixed structure 101, which itself comprises a fixed nozzle duct 110 terminated, on the downstream side, by an annular reinforcing gutter 111, over the outer periphery of which there are provided yokes 112 which are spaced apart from one another in the peripheral direction of the nozzle. The fixed nozzle duct 110 also carries, on its outer periphery, a ring of lugs 113.

The fixed structure 101 also comprises a plurality of longitudinal side-plates 114a, 1141). In the vicinity of its upstream end, each of these side-plates is hinged about an axis G, to a yoke 115a (1151)) which is itself hinged about an axis H, to a rocking lever 116 which is in turn hinged, about an axis J, to two lugs 113 which are con secutive in the peripheral direction. Further downstream, each of the side-plates 114a, 114b is likewise hinged about an axis K, to a yoke 112. As will be realized, this method of attaching the side-plates makes it possible to make allowance for their expansion during operation.

The fixed nozzle duct 110 is succeeded by a ring of adjustable flaps comprising, on the one hand, the actuated flaps 102, and, on the other hand, follower flaps 122.

Each actuated flap 102 comprises a leaf 102x to which there is fastened a cranked lever 102y. The latter is hinged about a first geometrical axis A which is substantially tangential in relation to the nozzle, to two, peripherally consecutive, side-plates 114a, 114b, which form part of the fixed structure 101.

The follower flaps 122 are respectively located between the actuated flaps 102, and are applied, during operation, against the internal flanges of their neighbours by the pressure of the jet of gases which passes through the nozzle. I

An annular seal plate 123 ensures tightness at the joint between the fixed nozzle duct 110 and the flaps 102-122.

Each actuator 103 associated with an actuated flap 102 is enframed by two, peripherally consecutive, sideplates 114a and 114b, and has, at its upstream end, two lugs 103a, 103b by means of which the body of the said actuator is hinged, about the aforesaid axis G, to the said side-plates.

An intermediate (or synchronization) lever 105 is disposed, as has been stated, between two successive actuated flaps 102. This intermediate lever is hinged, about a second axis B which is substantially tangential in relation to the nozzle, to two, peripherally consecutive side-plates 114a and 114b.

There will also be seen, in these Figures, the two connecting rods 106a, l06b by means of which each actuated flap 102 is connected, respectively, to the two intermediate levers 105 which enframe it. As can be seen, each connecting rod 106a or 106!) is hinged, on the one hand, to the cranked lever 102y forming part of an actuated flap 102, about a third axis C which is substantially tangential in relation to the nozzle and, on the other hand, to an intermediate lever 105 adjacent to the said flap, about a fourth geometrical axis D which is substantially tangential in relation to the nozzle.

As can be seen in FIG. 6, the four axes of articulation, A, B, C, D, are disposed in such a way, relative to one another, that their respective traces, onto the plane of the said Figure, substantially form the four vertices of a deformable parallelogram ABCD having a fixed side AB. The height, which is variable, of this parallelogram is constituted by the distance between the said side AB and the side CD opposite the latter.

Finally, the cross-bar 107 already mentioned above will again be found in these Figures. Each cross-bar 107 is hinged, about the aforesaid axis E, to the two interconnecting links 106a, 106b which are associated with the same actuated flap 102.

As is more particularly shown in FIG. 6, the point E is selected in such a way that its distance from the fixed side AB of the parallelogram ABCD is, at any moment, less than the height of the said parallelogram.

As can be seen in FIGS. 4 and 5, it is to this cross-bar 107 that the end of the moving rod 104 of the actuator 103 associated with the said flap, is fixed, by means of a pin 125.

The functioning of the nozzle thus described is substantially the same as heretofore known. The unit made up of the actuated flaps 102, the synchronization levers 105 and the connecting rods 106a, 1061) constitutes an indented kinematic chain which is closed around the nozzle and compels each of the actuated flaps to adopt a mean position which is common to all the flaps. Under all its operating conditions, therefore, the nozzle thus retains a circular transverse section which is concentric with itself, even in the event of dissymetry in the functioning of the actuators jacks 103 for the said flaps.

Furthermore, the special arrangement according to the present invention, in which the rod 104 of the actuator 103 is fastened to a cross-bar 107 which is itself hinged to the two connecting rods 106a, 106k about an axis E, the location of which is selected as has been stated, provides the major advantages already mentioned above in connection with Figure 3.

The present invention applies both to single nozzles made up of an only ring of flaps (as is the case with the nozzle which has just been described), and to ejector type nozzles comprising two rings of actuated flaps which are respectively associated with a primary nozzle duct and with a secondary nozzle duct (as is the case with the nozzle described in the prior art.

The present invention which, as has been seen, leads to a substantial reduction in the overall dimension, in the radial direction, involved by the actuators can also be put into practice in an advantageous manner in the case of an exhaust unit comprising two primary nozzles disposed inside a single nacelle. In this case, for the purpose of reducing the base drag of the exhaust unit as far as possible, it is advantageous, as is already known, to bring the two nozzles as close together as possible, and it is precisely this which the invention makes it possible to obtain.

We claim:

1. A jet propulsion nozzle having an adjustable crosssectional area, of the type comprising:

a fixed structure comprising a fixed nozzle duct;

a plurality of actuated flaps which are distributed circumferentially around, and in the prolongation of, the downstream part of the said fixed nozzle duct, and of which each one is hinged, about a first geometrical axis which is substantially tangential in relation to the nozzle, to the said fixed structure, in such a way as to vary the cross-sectional area of the said nozzle;

a plurality of actuators, each of which corresponds to an actuated flap and comprises a moving part which makes it possible to rotate the said flap about the said first geometrical axis;

a plurality of intermediate levers which are disposed a plurality of connecting rods, each of which is hinged, on the one hand, to an actuated flap, about a third geometrical axis which is substantially tangential in relation to the nozzle and, on the other hand, to an intermediate lever adjacent to the said flap, about a fourth geometrical axis which is substantially tangential in relation to the nozzle, in such a way that there are associated with each actuated flap, two connecting rods by means of which the said flap is connected, respectively, to the two intermediate levers which enframe it; the said first, second, third and fourth geometrical axes, which relate to an actuated flap and to an intermediate lever adjacent to the latter, being disposed in such a way, relative to one another, that the quadrilateral which they determine by their respective traces onto a plane containing the axis of the nozzle, is substantially a parallelogram which is deformed during variations in the crosssectional area of the nozzle, the said deformable parallelogram having a fixed side constituted by the segment of straight line which connects the traces, on the said plane, of the said first and second geometrical axes, and a moving side which is substantially parallel to the said fixed side and is constituted by the segment of straight line which connects the traces, onto the same plane, of the said third and fourth geometrical axes, the said fixed side and the said moving side being separated from one another by a variable distance which constitutes the height of the deformable parallelogram, in which the moving part of the actuator corresponding to an actuated flap, is fastened to a cross-bar which extends in a substantially tangential direction, relative to the nozzle, and connects the two connecting rods associated with said flap, and in which the trace of this cross-bar onto the plane of said deformable parallelogram, is separated from the fixed side of said parallelogram, at any moment, by a distance which is smaller than the height of said parallelogram. 

1. A jet propulsion nozzle having an adjustable cross-sectional area, of the type comprising: a fixed structure comprising a fixed nozzle duct; a plurality of actuated flaps which are distributed circumferentially around, and in the prolongation of, the downstream part of the said fixed nozzle duct, and of which each one is hinged, about a first geometrical axis which is substantially tangential in relation to the nozzle, to the said fixed structure, in such a way as to vary the cross-sectional area of the said nozzle; a plurality of actuators, each of which corresponds to an actuated flap and comprises a moving part which makes it possible to rotate the said flap about the said first geometrical axis; a plurality of intermediate levers which are disposed in alternation with the said flaps and each of which is hinged about a second geometrical axis which is substantially tangential in relation to the nozzle, to the said fixed structure; a plurality of connecting rods, each of which is hinged, on the one hand, to an actUated flap, about a third geometrical axis which is substantially tangential in relation to the nozzle and, on the other hand, to an intermediate lever adjacent to the said flap, about a fourth geometrical axis which is substantially tangential in relation to the nozzle, in such a way that there are associated with each actuated flap, two connecting rods by means of which the said flap is connected, respectively, to the two intermediate levers which enframe it; the said first, second, third and fourth geometrical axes, which relate to an actuated flap and to an intermediate lever adjacent to the latter, being disposed in such a way, relative to one another, that the quadrilateral which they determine by their respective traces onto a plane containing the axis of the nozzle, is substantially a parallelogram which is deformed during variations in the cross-sectional area of the nozzle, the said deformable parallelogram having a fixed side constituted by the segment of straight line which connects the traces, on the said plane, of the said first and second geometrical axes, and a moving side which is substantially parallel to the said fixed side and is constituted by the segment of straight line which connects the traces, onto the same plane, of the said third and fourth geometrical axes, the said fixed side and the said moving side being separated from one another by a variable distance which constitutes the height of the deformable parallelogram, in which the moving part of the actuator corresponding to an actuated flap, is fastened to a cross-bar which extends in a substantially tangential direction, relative to the nozzle, and connects the two connecting rods associated with said flap, and in which the trace of this cross-bar onto the plane of said deformable parallelogram, is separated from the fixed side of said parallelogram, at any moment, by a distance which is smaller than the height of said parallelogram. 